1. Field of the Invention
This invention relates to apparatus for successively feeding articles to a work station, and more particularly to a high speed article feeding apparatus incorporating an automatic sequencing circuit for controlling the operation of the several elements thereof.
2. Description of the Prior Art
There are various types of known apparatus for successively feeding articles from a feed position to a work station where one or more operations are performed thereon, and which is thereafter conveyed from the work station and another article is brought thereto. Although generally satisfactory for the intended purpose, the prior art feed devices are limited in the speed at which they can operate and sometimes involve misfeeds of articles, which can cause excessive down time of the apparatus.
In feed systems wherein the work pieces are gripped, conveyed to the work station, released from the conveying means, gripped by a holding means during the performance of the particular operation thereon and then released, the sequence of events must follow a predetermined order or a misfeed can occur. For example, in the apparatus illustrated and described in U.S. Pat. No. 4,059,212, which issued on Nov. 22, 1977, and which is owned by the assignee of the present invention, a stock feeder for punched stock is disclosed which utilizes a pneumatic circuit for actuating the several gripping and transporting means provided. That system relies on utilizing fluid passageways of differing cross-sectional areas in order to control the sequencing of the several operations. There are times, however, when a misfeed can occur to cause the operation to be temporarily halted while the misfeed situation is corrected. Additionally, the system therein disclosed operates using a plurality of limit switches to control the operation of the pneumatic circuit and the larger number of parts unnecessarily encumber the system and each are subject to malfunction or failure, thereby diminishing the reliability of the system.
It is therefore desirable to provide a system which overcomes the shortcomings in the prior art devices.